The Celtic inhabitants of Wales successfully maintained independence against the Anglo-Saxons who settled in England following the withdrawal of the Romans. Norman colonization from England began in the 12th century, and their control over the country was assured by Edward I's conquest （1277-84）. Edward began the custom of making the English sovereign's eldest son Prince of Wales. Wales was formally brought into the English legal and parliamentary system by Henry ⅤⅢ (1536), but has retained a distinct cultural identity. In 1997 a referendum narrowly approved proposals for a Welsh assembly, which was inaugurated in 1999.